Stove burner

ABSTRACT

A ceramic stove burner suitable for in-line installations in vertical combustion chambers such as hot blast stoves for blast furnaces, includes an annular exterior wall in alignment with the combustion chamber and an annular internal wall concentric therewith which forms a central mixing chamber and an annular chamber between the walls. A baffle is formed in the inner wall having at least one row of combustion air apertures which are skewed relative to the mixing chamber so as to be inclined both upwardly and obliquely thereinto. Gas enters into the mixing chamber near the bottom thereof and is mixed with the combustion air which forms a swirling flow pattern in a convergent manner.

United States Patent Hovis et al.

[ 1 June 24, 1975 STOVE BURNER OTHER PUBLICATIONS [75] Inventors: James Hows jfferson MohrRaco Ceramic Stove Burners lron zmi Steel Allegheny County James Johns; Engineer October 1971 page 8-17 Harry P. Finke, both of Pittsburgh, all of Pa. 0 Primary Examiner-Carroll B. Dority, Jr. l l Asslgnee: Bloom Engmeermg Company Inc, Attorney, Agent, or FirmWebb, Burden, Robinson &

Pittsburgh, Pa. Webb [22] Filed: Nov. 5, 1973 21 Appl. No.1 412,667 1 1 ABSTRACT A ceramic stove burner suitable for in-line installa- 152 us. (:1 432/217; 431/173 ions in vertical combustion chambers Such as hm 51 1m. (:1. F231 9/04 blast Stoves for blast furnaces includes an annular [58] Field of Search 432/217 218 182- wall alignment with mbusti0n chamber 431/173;v L and an annular internal wall concentric therewith which forms a central mixing chamber and an annular I 56] References Cited chamber between the walls. A baffle is formed in the inner wall having at least one row of combustion air UNITED STI'KTES PATENTS apertures which are skewed relative to the mixing 2,918,118 12/1959 Schmner 431/352 chamber so as to be inclined both upwardly and g obliquely thereinto. Gas enters into the mixing chamx g rigg i 432/2 ber near the bottom thereof and is mixed with the 17791690 12/1973 Rossow I: 1:: 431/173 forms swi'ling flow Patter c r n FOREIGN PATENTS OR APPLICATIONS g 413,283 5 1925 Germany 431 173 6 Claims 4 Drawmg guns 4 ,3: 22 g wo 2O J V ,j/

0, 0 0 ty ls is 4 Z/ x 0 0\" 6 i l4 O I '74/ Q l r x :1: F 1: 4 j

a c IO/\ \II; 2} :j/ 2|M; z 7: I I '71 l6 j/, /j/ l/ x 1; u 1 if '1 ::l-\\\ 2 STOVE BURNER FIELD OF THE INVENTION Our invention relates to burners and, more particularly, to ceramic stove burners suitable for in-line installation within a vertical combustion chamber such as a hot blast stove for a blast furnace.

DESCRIPTION OF THE PRIOR ART Blast furnace stoves are employed to preheat the air blast before it is admitted into a blast furnace through the tuyeres. The stove consists of twoparts which are the combustion chamber where cleaned blast furnace gas is burned and the checkerwork through which the products of combustion from the blast furnace gas pass. The checkerwork portion of the stove can be constructed to provide a two pass, three pass or four pass system, but in all designs there is a single combustion chamber. The burners for the combustion chamber are either side fired or vertically fired in alignment with the combustion chamber. The side fired combustion cham bers include a burner which directs the combustibles at a target wall (causing target wall failures) so as to be deflected upward into the combustion chamber. While vertical burners provide an in-line firing of the combustibles, they have a tendency to plug up as the result of particles of brick and brick dust which settle to the bottom of the combustion well in the area of the burner and the burner holes. These combustion chambers are often in excess of 100 feet high and, therefore, there is substantial dust and brick particles which fall from the combustion chamber during normal usageln addition, both types of burners must provide uniform air distribution and proper mixing and achieve complete combustion in the combustion chamber.

A vertical burner has been proposed which provides air passages which are inclined upwardly into the mixing chamber to assist in the mixing of the combustion air and gas. However, such a system utilizes apertures in the port block which are subject to plugging as the result of the brick particles and brick dust. In addition, mixing occurs only through radially inclined combustion air passageways thereby increasing the risk of unburnt combustibles over the subject stove burner.

SUMMARY OF THE INVENTION We have designed a vertically firing ceramic stove burner which provides proper mixing, uniform air distribution and complete combustion, and at the same time, is positioned so that the apertures through which the combustion air and gas enter are not subjected to plugging by the brick particles and brick dust which fall into the burner from the brickwork of the combustion chamber.

Our invention is a ceramic stove burner which is vertically installed in a combustion chamber. The burner comprises an annular exterior wall in alignment with the chamber and a concentric inner wall which forms an annular chamber between the walls and a central mixing chamber. A baffle forms part of the inner wall and includes at least one row of combustion air apertures which are skewed relative to the mixing chamber so as to be inclined both upwardly and obliquely thereinto. All openings are along vertical surfaces so that they are not readily plugged by materials falling through the combustion chamber into the burner. The mixing chamber is normally elliptical-like in shape and sections of air apertures extend along the opposing sides of the major diameter of the elliptical-like shape.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a section taken through the ceramic stove burner along the vertical line thereof;

FIG. 2 is a section taken along section lines ll-ll of FIG. 1;

FIG. 3 is a section taken along section lines Illlll of FIG. 1; and

FIG. 4 is partly in section and illustrates the mixing chamber and air and gas inlets superimposed and the fuel and air mixing characteristics. I

DESCRIPTION OF THE PREFERRED EMBODIMENT The ceramic stove burner, generally designated 10, is situated at the bottom of a combustion chamber 11 normally made of stove refractories 23 and a combustion chamber metal skin wall 24, FIGS. 14. The combustion chamber 11 is a part of a blast furnace stove (not shown).

The stove burner 10 is positioned in the bottom portion of the combustion chamber 11 which is sometimes referred to as the combustion chamber well. The stove burner 10 is an independent self-supporting refractory unit and comprises an outer wall 12, an inner wall 13 and a baffle 18 formed in the inner wall, FIG. 1. The outer wall 12 is made up of standard refractory shapes mortared in place and situated inwardly of the stove refractory 23 which makes up the in wall of the combustion chamber throughout its height. The inner wall 13 is also made of standard refractory shapes and it is annular in shape and is concentrically located within the outer wall 12. Both the inner and outer walls 13 and 12 extend in line along the vertical center line of the combustion chamber 11.

The outer wall 12 and inner wall 13 define an annular chamber 14 therebetween. The inner wall 13 defines a central mixing chamber 15. The mixing chamber has a cross section which approaches being elliptical in that there is a major and minor diameter although there can be a variety of departures from a true elliptical cross section. The term elliptical-like" as used herein defines the true ellipse, as well as the various departures therefrom which include a major and minor diameter, FIG. 3. An air inlet 17 extends through the stove refractory 23 and outer wall 12 to communicate with chamber 14. A gas inlet 16 extends through the stove refractory 23 and the inner and outer walls 12 and I3, respectively to communicate with the mixing chamber 15 near the bottom thereof, FIGS. 1 and 2. The space formed between the outer wall 12 and inner wall 13 in the area of the gas inlet 16 is filled with a castable refractory 21 which defines the bottom of the annular chamber 14. An inclined refractory wall 20 connects the outer wall 12 with the inner wall 13 at the top thereof to form the upper boundary of chamber 14 and this inclined wall 20 acts as the port block for the burner. The connecting wall 20 is imperforate and there are no openings extending through or into the port block from the annular chamber 14.

A baffle 18 made of refractory shapes is formed integral with the inner wall 13 near the top of the mixing chamber 15 and below the connecting wall 20. The baffle 18 includes a plurality of apertures 19 which extend through the wall l3 to place the chamber 14 in communication with the mixing chamber 15. The apertures 19 are inclined upwardly through wall 13 and are inclined obliquely into the mixing chamber 15. This combination of upward and oblique inclinations causes the air which passes through the apertures 19 to develop an inwardly swirling flow in a convergent pattern, see FIG. 4 where the air pattern is illustrated by curved arrows 2S and the blast furnace gas is illustrated by straight arrows 26. The apertures 19 are positioned in two sections on opposing sides of the major diameter of the elliptical-like mixing chamber 15. Either a single row of air apertures can be employed or a plurality of rows can be employed as illustrated in FIG. 1.

The multiple apertures 19 restrict the air thereby forming a uniform air distribution in an annular chamber 14 even though the air inlet 17 enters chamber 14 at a single location.

An igniter or high pressure pilot burner 22 extends into the combustion well above the mixing chamber 15 to ignite the combustibles, FIG. I.

The operation of our ceramic stove burner is as follows. The blast furnace gas enters the mixing chamber 15 at the bottom thereof through inlet port 16 which is connected to gas valving (not shown). The blast furnace gas flows upwardly along the axial center line of the mixing chamber 15. Combustion air enters the annular chamber 14 through the air inlet 17 which is likewise connected to suitable air valving (not shown). The air which is evenly distributed in chamber 14 enters the mixing chamber 15 through the apertures 19 which are skewed upwardly and obliquely to cause a converging flow pattern and intimately mixes with the blast furnace gas passing through the mixing chamber. The high pressure pilot burner 22 installed above the ceramic burner provides combustion for the combustible mixtures passing thereby.

The above arrangement provides uniform air distribution into the mixing chamber, total mixing of air and gas and combustion within the combustion chamber. In addition, the brick particles and dust which drop from the combustion chamber collect in the bottom of the well and do not enter the air apertures. This debris which collects on the bottom of the ceramic burner can be routinely cleaned out and the substantial heat release is maintained since there is no blockage of the air or gas ducts leading into the mixing chamber.

We claim:

1. In combination. a vertical hot blast stove combustion chamber and a refractory burner spaced inwardly and independently of and concentrically within said combustion chamber, said refractory burner comprising an annular exterior wall in axial alignment with and positioned at substantially the bottom of the combustion chamber. a concentric inner vertical wall forming an annular chamber between said walls and a central mixing chamber, a gas inlet extending into the mixing chamber near a bottom end thereof, a combustion air inlet extending into the annular chamber. a baffle formed in the inner wall spaced upwardly of the air inlet and having at least one row of combustion air apertures extending through the vertical inner wall and into the mixing chamber, said apertures being skewed relative to the mixing chamber so as to be inclined both upwardly and obliquely thereinto to form a swirling flow pattern in a convergent manner.

2. The burner of claim 1 including an imperforate annular inclined wall connecting the inner wall and the outer wall at the top of the mixing chamber.

3. The burner of claim 1 including a plurality of rows of combustion air inlets.

4. The burner of claim 1, said inner wall, outer wall and baffle being formed of refractory shapes.

5. The burner of claim 1 wherein said inner and outer walls are elliptical-like in cross section.

6. The burner of claim 5 wherein each row of apertures includes a first and second series of apertures, the respective series being positioned on opposite sides along the major diameter of the elliptical-like shape. 

1. In combination, a vertical hot blast stove combustion chamber and a refractory burner spaced inwardly and independently of and concentrically within said combustion chamber, said refractory burner comprising an annular exterior wall in axial alignment with and positioned at substantially the bottom of the combustion chamber, a concentric inner vertical wall forming an annular chamber between said walls and a central mixing chamber, a gas inlet extending into the mixing chamber near a bottom end thereof, a combustion air inlet extending into the annular chamber, a baffle formed in the inner wall spaced upwardly of the air inlet and having at least one row of combustion air apertures extending through the vertical inner wall and into the mixing chamber, said apertures being skewed relative to the mixing chamber so as to be inclined both upwardly and obliquely thereinto to form a swirling flow pattern in a convergent manner.
 2. The burner of claim 1 including an imperforate annular inclined wall connecting the inner wall and the outer wall at the top of the mixing chamber.
 3. The burner of claim 1 including a plurality of rows of combustion air inlets.
 4. The burner of claim 1, said inner wall, outer wall and baffle being formed of refractory shapes.
 5. The burner of claim 1 wherein said inner and outer walls are elliptical-like in cross section.
 6. The burner of claim 5 wherein each row of apertures includes a first and second series of apertures, the respective series being positioned on opposite sides along the major diameTer of the elliptical-like shape. 